Apparatus for imposing tension on running yarn



Sept. 11, 1962 ZIMMERMAN, JR 3,053,473

APPARATUS FOR IMPOSING TENSION 0N RUNNING YARN Filed March 10, 1960 W M I INVENTOR YARN LEON HERSHEY ZIMMERMAN JR.

BY 7M 98 ATTORNEY United States Patent 3,053,473 APPARATUS FOR IMPOSING TENSION 0N RUNNING YARN Leon Hershey Zimmerman, Jr., Kinston, N.C., assrgnor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Mar. 10, 1960, Ser. No. 14,148 1 Claim. (Cl. 242-149) The present invention relates to a process and apparatus for the unwinding of yarn from packages under tension. More particularly, it relates to an improved process and apparatus which prevents a traveling yarn from freeing itself during interruptions in the unwinding and rewinding of textile yarns.

In the warping of textile yarns, such as in the winding of yarn beams from a multiplicity of small packages, it is common practice to pass the yarn from the individual packages which are held on a creel through a suitable tension device in order to provide the tension required to wind a satisfactorily compact beam of yarn.

For the imposition of tension, the disc and post type of tension device is frequently used in view of its simplicity (U.S.P. 2,735,632). This device consists of one or two discs mounted on a centrally located post. The yarn is passed over one disc or between two discs and snubbed around the post. 'One or more of these devices may be employed to achieve the desired tension level. However, difficulty is sometimes encountered with this type of tension device in that the yarn tends to free itself from the disc when the winding of the yarn is suddenly interrupted as happens when the winder is stopped to permit repair of thread breaks or for other reasons. The problem is particularly severe With yarns of high filament denier or any yarn which is sufiiciently stifl to resist bending. Variable denier yarns which do not run smoothly through the tension device are particularly bothersome in this respect.

It is an object of the present invention to provide a process wherein the tendency of a yarn to free itself from disc and post type of tension devices in the unwind ing and rewinding of yarn packages is substantially eliminated. Another object is to provide a simple apparatus which is particularly adapted to be used in the conventional warping or beaming of textile yarns.

The above objects are accomplished by the present invention which provides an improvement in the process for the warping of textile yarns from a multiplicity of small yarn packages by snubbing the individual package yarn around a post to impose tension thereon and winding the individual yarns on a common core, the improvement comprising restrictively pretensioning each of the individual yarns prior to snubbing around the post.

The improved process is accomplished by the use of an apparatus for imposing tension on a running yarn while restricting the movement of the yarn during winding interruptions which comprises an eyelet, a cylindrical freely rotating tension weight with one end of the said tension weight resting on the upper surface of the eyelet and covering the eyelet opening, and a retaining means to hold the said weight in a position eccentric of the center of the eyelet opening while permitting rotation of said weight.

The improved apparatus is particularly useful in combination with a disc and post type of tensioning apparatus and the combination comprises (A) a smooth disc and post, the said post being substantially perpendicular to and concentric with the disc face, and (B) an eyelet in spaced relationship to the said disc and post and on a plane substantially corresponding to that of the face of the said disc, said eyelet having a cylindrical freely rotating tension weight resting on the upper surface of the eyelet and covering the eyelet opening, the said tension weight being held in a position eccentric to the center of the eyelet by a retaining means.

The terminology snubbing the individual package yarns around a post to impose tension thereon and winding the individual yarns on a common core is used to signify the conventional process whereby a plurality of individual yarns are unwound from yarn packages and rewound on a single core or support such as in the warping or beaming of yarns. By restrictively pretensioning is meant that a tension or drag is imposed on the yarn prior to its passage around the post and, at the same time, the yarn is restricted in motion and in that the backward passage and sideway motion of the yarn is prevented and it remains properly positioned in the eyelet and on the post.

In the accompanying drawing, which illustrate preferred embodiments of the invention:

FIGURE 1 is a diagrammatic view of the pretensioning apparatus of the present invention in cross section;

FIGURE II is a diagrammatic view partially in crosssection of the pretensioning apparatus of FIGURE I in combination with the conventional disc and post type of tensioning device.

In FIGURE I, the yarn travels through the eyelet 3 and out of the open portion of the retaining means 2. A cylindrical tension weight 1 covers the eyelet opening and is held in position by the hollow opening of the retaining means 2. The tension weight 1 is free to rotate in the opening of the retaining means 2 and does so as winding proceeds due to its eccentric location over the eyelet 3. The eyelet may be made of any suitable material such as plastic or metal but is preferably made of a ceramic material with the yarn contacting surfaces being polished. The corners which contact the yarn should be rounded to prevent damage to the yarn. The size of the eyelet is not critical and may be selected as desired for convenience in threading and installation. The flange at the end of the eyelet 3 provides a substantially flat polished surface for contacting the yarn. The dimensions of the flange are in accordance with the size of the tension weight employed. The cylindrical tension weight 1, which rests on the flanged surface of the eyelet to provide the necessary resistance against movement of the yarn between the two surfaces, may be made of various materials althrough it is preferred that it be made of steel with a chromium plate bottom surface that can be highly polished. A uniform matte finish may also be employed on the bottom surface. The diameter of the cylindrical tension weight is preferably close to that of the eyelet flange but may obviously be varied somewhat if desired. The mass of the cylindrical tension weight may be adjusted to achieve the desired tension. For convenience a projecting piece of smaller diameter than the cylindrical tension weight may be provided as shown in FIGURE I to facilitate removal of the weight for threading of the eyelet or for other purposes.

In FIGURE II, the tubular eyelet 6 is inserted through the smaller, lower hole in the retaining means 5 while the cylindrical tension weight 4 is placed in the larger opening so that it rests on the flange of the eyelet and covers the eyelet opening. The two circular holes in the retaining means are eccentric with respect to one another so that the cylindrical tension weight is held in an eccentric position with respect to the center of the eyelet. This eccentricity causes the tension weight to rotate as the yarn is passed through the device thus making it self cleaning and preventing the formation of grooves in the weight. The assembled pretensioning device mounted in position adjacent to the conventionad disc and post type tension device (as shown) represents a preferred embodiment of the present invention. An additional disc (not shown), similar to disc 8, may be slid over post 7 to bear on the yarn and impose additional tension. The assembly is readily mounted in position by cementing the eyelet 6 and the retaining means 5 in position in a suitable support adjacent to the disc and post device. Additional disc and post tension devices may be added to impose further tension on the yarn.

In a specific embodiment of the present invention, viscose rayon yarn of 2700 denier is unwound from centrifugally wound bucket cakes held on a conventional creel. The yarn being unwound from the cakes is passed through a pretensioning device of the type illustrated in the drawings, The eyelet consists of a ceramic tube inch in length, and having an inside diameter of inch, an outside diameter of A inch and a flange at the top having an outside diameter of 1 inch. The inside of the tube and the upper surface of the flange are polished and the corners are rounded to provide a smooth yarn contacting surface. The cylindrical tension weight is of chromium plated steel with a diameter of inch, a length of inch and the lower, yarn contacting surface is polished to a mirror finish. A centrally located cylindrical projection of inch diameter and inch length is provided at the top of the weight to facilitate removal. The retaining means is molded from nylon resin. The lower circular opening is inch in diameter. The center of the upper, circular opening is offset from the center of the lower opening by inch. The yarn is passed upwardly through the eyelet and under the tension weight as shown in FIGURE II. The yarn is then passed through a disc and post type tension device without using an upper disc. The p retensioning device of the present invention is oriented with respect to the disc type tension device in such manner that the tension weight is eccentric with respect to the travel of the yarn and consequently the tension device rotates slowly as the yarn is drawn through the device. After passing through the disc type tension device the yarn is wound on a beam in the conventional manner. Yarn is unwound from a multiplicity of packages and rewound into a beam at a speed of 350 yards per minute without difliculty. When the tension device of the present invention is omitted, much difficulty is encountered due to the yarn freeing itself from the disc type tension device when the winding is interrupted for any reason.

Although the tension device of this invention is particularly useful in the warping of yarns where disc type tension devices are used, it obviously may be used in many other applications where tension must be applied to yarn. The device is simple to construct and the materials of construction and dimensions may be readily adapted to suit the particular application.

Many other equivalent modifications will be obvious to those skilled in the art from a reading of the above description without a departure from the inventive con cept.

What is claimed is:

An apparatus for imposing tension on a running yarn which comprises an eyelet in the form of a tube having an outward flange at one end, the flange providing a smooth surface at right angles to the axis of the tube, a support for mounting said eyelet with the flange upward so that the smooth surface is horizontal, a yarn guide spaced from said eyelet for guiding yarn along a fixed path in contact with said flange when threaded through the eyelet tube and run directly to the guide, a cylindrical weight having a plane end with the axis of the cylinder perpendicular thereto, said cylinder being supported on said eleyet flange with the cylinder axis parallel to said tube axis so that the plane end covers the tube and eccentrically overlaps said yarn path over the flange, and retaining means forming a bearing around the cylinder to keep the cylinder rotatably in position so that the Weight thereof on yarn running along said path will cause the cylinder to rotate while maintaining the yarn under tension.

References Cited in the file of this patent UNITED STATES PATENTS 1,785,987 Stewart Dec. 23, 1930 2,955,774 Letsch Oct. 11, 1960 FOREIGN PATENTS 410,403 Great Britain May 17, 1934 

